Day after day, the same tag line is completed with a topic from a list of the most pressing issues facing Los Angeles - and by extension, urban America: crime, racism, immigration, affirmative action, gangs, schools, politics.

Questions are answered by the broadest range of thinkers, movers, and shakers across the country who have been screened by producers and who call in using a bank of phone lines. They include politicians, activists, lawyers, corporate heads, entrepreneurs, ministers, gang members, other journalists, and ordinary citizens.

Next month comes the fifth anniversary of the show that, like ABC's "Nightline," was born in crisis but has grown to become a lasting and venerated institution. Five years after KCRW station director Ruth Seymore tapped Olney to host two weeks of shows, inquiring how communities might heal in the aftermath of the worst riots in US history here, Olney finds his job unfinished.

"Los Angeles is a laboratory, and the risks are great," he says in a signature baritone that is both affable and authoritative. "When your questions are how to maintain order and stability and how to survive this multicultural adventure, you're never done."

To explore his questions, Olney conjures the wisdom of his phone-in experts in a kind of intimate, round-table discussion beamed regionwide in live, on-air conversations. With a gift for dissecting complex arguments, Olney deftly questions, cajoles, and prods his guests, finding common ground between opponents and differences among those who think they agree.

The caliber of participants, the nonconfrontational format, and Olney's skill in impartially juggling the point/counterpoint have garnered a string of major national awards, a loyal following, and high ratings.

"For five years, 'Which Way, L.A.?' has been the most significant public conversation in the city," says Kevin Starr, a state historian who has written three books on California. "Because of its enormous expanse, the city hasn't had many devices for sorting itself out. Warren's show has become the major institution to distill that unwieldy sweep and scale into an accessible village."

Olney had spent 20 years in television news, capped as a local anchor for all three major networks (KABC, KNBC, KCBS). Briefly retired, he had lamented the shrinkage of serious broadcast news stories over time, from 10 minutes in his heyday to typically a minute and a half by 1990.

The immediate success of "WWLA" led to its permanence after a month. Now it boasts about 140,000 daily listeners, 10 to 15 percent above the station's average and a third of whom are black and Hispanic.

In a market with 90 other radio stations, those numbers may belie the real influence of the show as a must-listen for government officials and other newsrooms purporting to be in the know.

"Warren Olney has become the lone, intelligent voice in the vast wasteland of broadcast media in southern California," says Alan Heslop, director of the Rose Institute at Claremont McKenna College. "His appeal ranges across a number of categories of society - intellectuals and academics but also to ordinary people."

That cross-fertilization between issue insiders and outsiders, across a mixture of topics that affect all corners of the city, is precisely why the show's mandate is so important, according to Ms. Seymore.

"Los Angeles is a city like no other in that it is a collection of different centers that are highly indifferent to one another," she says. "Unlike other cities, we have to keep asking, 'Is L.A. interested in L.A.?' "

The past five years have been particularly trying for the 88 communities and 149 ethnic groups that make up the patchwork quilt of Los Angeles. Drought, freeze, fires, mudslides, earthquakes, and riots add to a list topped by major, racially charged trials - two each for Rodney King and O.J. Simpson. What often draws listeners to "WWLA" is that the major players in these and other issues are speaking up before public policy is settled. Listeners get to hear the ticking minds of key news participants ahead of the news.

They also get to hear them in depth. With about seven to 10 guests per show, and no commercial interruptions, Olney typically spends the full hour examining just one topic. And because of Los Angeles's role as America's bastion of cultural experimentation, discussions fly beyond standard public-affairs fare: rap music, media mergers, TV ratings, the new urbanism, generation X.

"We have great luxury in Los Angeles because every culture in the world is here," says Olney. "One of our basic questions is to ask the very challenging question of multiculturalism: Can we all live together this way?"

He feels radio can deliver more depth than TV because listeners are not distracted by pictures. Likewise, participants on his radio show are more candid than usual because they join in only by phone from the security of their own surroundings.

If there is a downside to the show, observers say, it might be that Olney's smooth and unopinionated temperament doesn't provide the type of sparks and controversy that generate major ratings. In appealing to a smaller, more educated, more monied - critics say "elite" - audience of public radio, Olney does not resort to the personalized antics of such figures as conservative provocateur Rush Limbaugh or shock-jock liberal Howard Stern.

"The issues we face here are ones coming to every American city," says Olney. "The struggles we are having will be a lesson for municipalities coast to coast."